Vinegar works great also as a PH down! (Baking soda is a natural PH up also)I grow in soil and my house water is well above 7. I collect rainwater for plant water which helps get the soil ph down in the high 6's
Rain water has EXTREME low alkalinity. Although this is what cannabis plants naturally drink, it Isn't optimal for them for vigor growth. Unless you have a great super soil. Dolomite lime in your medium really helps regulate your PH at the soil level. Therefore not needing to be so cautious about PH'in your water.